US stock index futures pointed to a mixed open on Wall Street today as corporate and political leaders began a three day summit in Davos, Switzerland and after US President Barack Obama used his last State of the Union speech to paint himself as the champion of the middle class, by demanding higher taxes for millionaires and tight reins on Wall Street. European shares fell, weighed down by the tech sector after a sharp post-results decline for World No.1 mobile gear maker Ericsson, and as investors worried that Greece may face a disastrous default.